Grinding machine



1941. F. JJTHELER 2,249,065

' GRINDING MACHINE Filed May 23, 1940 s Sheets-Sheet 1 ATTORNEY.

July 15, 1941. F. J. THELER GRINDING MACHINE Filed May 23, 1940 3 Sheets-Sheet 2 ATTORNE Y.

July 15, 1941. F. J. THELER GRINDING MACHINE Filed May 23, 1940 5 Sheets-Sheet 3 .xbc .5

INVENTOR. fifpflP/cmfii/afi A TTORNEY.

NM H a Patented July 15, 1941 GRINDING MACHINE Frederick J. Theler, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application May 23, 1940, Serial No. 336,820

' 13 Claims.

v vide an improved grinding machine by which a surface of revolution may be ground on a work piece in precision concentric relation to a preformed surface of revolution thereon which has been finished by a previous operation.

Another object of this invention is to provide an improved grinding machine for grinding conical surfaces on work pieces having preflnished conical surfaces, and in such manner that the axis of the new surface is coincident with the axis of the preflnished surface. I

A further object of this invention is to provide an improved grinding machine for grinding internal conical surfaces on work pieces having prefinished external conical surfaces and in such manner that the surfaces intersect in a circle concentric to the axis of the prefinished surface.

A still further object of this invention is to provide in grinding machines, improved means for supporting and rotating a work piece so that the axis of rotation will be coincident with the axis of a prefinished surface of revolution on the work piece.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is an elevational view partly in section showing the general arrangement of a machine embodying the principles of this invention.

Figure 2 is a plan view of the machine shown in Figure 1.

Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 1 showing the work clamping means and the relationship of the grinding wheel to the work.

Figure 4 is an enlarged section on the line 44 of Figure 1 showing the work rest blade.

, Figure 5 is a section on the line 5-5 of Figure 1 showing the control mechanism for the work clamping means.

In Figure 1 of the drawings the reference numeral It indicates in general the bed of the machine upon the top of which a headstock, indicated generally by the reference numeral II, is slidably supported for movement along guideways I2. Adjustment of the headstock longitudinally of the bed is effected by rotation of the lead screw l3 which engages a nut H depending from the underside of a sub-support It for the headstock, the screw being held against axial movement in the bearing l5 integral with the bed. The hand wheel I6 is attached to the end of the screw for convenience in rotating the same.

The longitudinal adjustment of the headstock by the screw I3 is in a direction which is parallel to the plane of rotation of a grinding wheel IT. This grinding wheel, as shown in Figure 3, is attached to the end of a spindle l8 which is journaled in bearings formed in the housing I9. The grinding wheel spindle is adapted to be driven by a prime mover, such as the electric motor 20,

mounted on top of the grinding wheel support 2! and connected to the spindle through conventional pulley and belt means enclosed in the housing 22. The grinding wheel support is pivotally mounted on a shaft 23, the axis of which is located below'the axis of the grinding wheel so that upon oscillation of the support 2| the grinding wheel moves substantially in a straight line toward and from the work. At the rear of the support 2| is mounted a hardened abutment 24 which engages the upper end of a follower 25 which is guided for vertical movement in the bed and has a roller 26 engaging the periphery of an eccentric cam 21. The cam is so formed that rotation through a predetermined arc in one direction will cause the rear end of the grinding wheel support to rise, whereby the grinding wheel will move toward the work and rotation in the other direction will cause the grinding wheel support to fall, thereby retracting the grinding wheel from the work.

The cam 21 is attached to the end of a shaft 28 which extends the length of the machine and into a housing 29 mounted on the end of the bed which contains certain control mechanism as more particularly shown in Figure 5. The shaft 28 has a pair of integral radially extending cars 30 which alternately engage adjustable stops II which limit the angle of rotation of the shaft 28. For convenience of operation the shaft extends beyond the housing and is provided with an operating lever 32. The headstock II has a spindle 33 journaled therein and the end ofthe spindle is provided with a face plate or platen 34 against which the work is clamped. The spindle is driven by an' electric motor 35 located on top of the headstock and connected by belt and pulley means enclosed in the casing 36 to a countershaft 31. The countershaft is connected by multiple belts 38 to a pulley 39 fixed with the spindle 33.

A tapered roller bearing member 40 has been selected as exemplifying a work piece which is particularly adapted to be finished in this machine. The work piece 40 comes to the machine with a finished conical surface 4|, and an end face 42 which is finished to lie in a plane perpendicular to the axis 43 of the conical surface 4| thus forming a base for the cone. The problem involved herein is to grind on the work piece a second conical surface 44 which is concentric to the cone 4| and therefore has its axis coincident with the axis of cone 4 I.

In the example shown, the cone 44 is an internal cone positioned to intersect the cone 4! and form an abutment for rollers mounted on the cone 4| when the parts are assembled in a roller hearing. If the conical surfaces are concentric, they will intersect in a circle which is concentric to the axis of the cone 4| and lies in a plane perpendicular to the axis 43,

Since the conical surface 44 is generated by revolution of the work about an axis it will be apparent that if the surface is to be concentric to the preformed surface it must be generated about an axis which is coincident with the axis of the preformed surface. It, therefore, becomes necessary that the work must be so supported and driven that it will rotate about the axis of the preformed surface whereby the new surface generated by revolution will be concentric therewith. Since the work piece has no centers, and since there is no guarantee that the bore of the work piece is concentric to the prefinished conical surface, means are provided for utilizing the prefini-shed surf-ace itself to determine the axis of rotation.

This is accomplished by considering the preformed surface as a journal, and providing a bearing member for the journal in the form of a work rest blade. By rotating the work while thus supported it will be apparent that the axis of rotation and the axis of the conical surface are coincident. Thus, any other surface formed on the work piece by revolution will have an axis which is coincident with the axis of the preformed surface.

The work rest blade 45, as shown in Figure 4, is attached for vertical adjustment to the base 45 of the headstock by a clamping screw 41. The work rest blade has a V-shaped notch 48 in the V-faces of which are hardened inserts 49 which engage the periphery of the conical surface 4 I. The blade 45 is arranged parallel to' the plane of the face plate 42 and the V-faces are made contrageneric to the tapered surface of the cone whereby when the cone is supported on the top of the work rest blade the axis of the cone is parallel to the axis of rotation of the face plate and therefore perpendicular to the plane of the face plate. Since the end face 42 of the work piece is preformed perpendicular to the axis of the cone, the end face 42 may be placed in engagement with the face plate 34, without cocking the work with respect to the blade or disturbing the perpendicular relationship of the work axis with respect to the plane of the face plate. Thus, the: position of the work, both laterally and axially, is determined. Means are provided for rotating the work while insuring that the work does not movev from this position during power rotation to effect the grinding action.

To insure that the work remains in engagement with the work rest blade, the blade is so positioned and adjusted that the axis of rotation 43 of the work is eccentric to the axis of rotation 34 of the face plate whereby a centrifugal or forwardly and downwardly reacting force is developed upon rotation of the face plate in a direction to urge the work into engagement with the work rest blade while rotating said work. The face plate rotates in a counterclockwise direction as viewed from the left of the machine as shown in Figure l and the grinding wheel rotates in a clockwise direction as viewed in Figure 1 and therefore the portions of the work and grinding wheel which are in contact move downward together toward the work rest blade as viewed in Figure 4. The relative feeding movements of the platen and grinding wheel accentuate the grip of these parts, on the work and their tendency to hold the work satisfactorily down into the V trough of .the work rest so that it will be positively accurately positioned for the concentric generation of the surface 44 with respect to the surface 4|.

To insure that the centrifugal or work driving force resultant is downward and toward the center of the work rest blade the axis of rotation 43 of the work is below and to the left of the axis of rotation 34' of the face plate as shown in Figure 4.

To prevent axial movement of the work during the grinding operation, a pressure head 55 is supported by antifriction means 5| on the end of a rod 52 which is slidably supported in an elongated piston rod 53. A piston 54 is integral with the piston rod and is slidabiy mounted in a cylinder 55. I

A spring 58 is interposed between the end of the piston rod 53 and a flange 51 formed on the rod 52 whereby the head is continuously urged toward the work. The rod 52 is freely slidable through the center of the piston rod 53 and on the other end is provided with an adjustable stop 58 and is preferably axially aligned with the axis of rotation of the work, obviating any necessity for eccentric slippage of the outer end of the work piece with respect to the head 50.

Compressed air is adapted to be admitted to the cylinder 55 to shift the pressure head 55 into engagement with the end of the work, and a spring 55 acts as a compensating means whereby the head 53 may take up slightly different positions depending upon the thickness of the work for the same position of the piston 54. When the piston is retracted it engages the stop 58 and thereby withdraws the pressure head from engagement with the work. The spring 58 must be sufficiently strong to hold the work piece in frictional engagement with the face plate whereby the face plate will rotate the work through friction which must necessarily be a sliding friction to a certain degree on account of the work being supported eccentric to the axis of rotation of the face plate.

The opposite ends of the cylinder 55 are connected by pipes 58 and 50 to a control valve 5| which is shown in Figure 5. This valve has a plunger 62 in the end of which is mounted a roller 53 which engages the end of a bell crank 64. The other arm of the bell crank has a roller 65 which engages the periphery of a control cam 66 fixed on the shaft 28. A spring 61 is interposed between .the end of the plunger '2 and a plug 68 in the end of the valve block for continuously urging the plunger in one direction to effect counterclockwise rotation of the bell crank and thereby maintain the follower roller 8! in engagement with the periphery of the cam 88. The valve block has a pressure port 68 which is adapted to be connected to any suitable source of pressure and a pair of exhaust ports 10 and 1 I. The valve plunger 62 is an ordinary reversing valve plunger having a pair of annular grooves 12 and 13 formed therein whereby the pressure port 69 may be alternately connected to pipes 59 and 60 while the other is connected to reservoir. The cam 66 has a receding portion 14 whereby when the shaft 28 is rotated by the manual control lever 32 into a position to effect retraction of the grinding wheel the pressure head will be withdrawn from engagement with the work and vice versa.

It will now be obvious that the method of operating the machine consists in placing a work piece on the work rest blade, throwing the lever to effect clamping of the work against the face plate, which is continuously rotating, and continuing movement of the lever to feed the grinding wheel to the work. The infeed limiting stop 3| in Figure is set to stop the feeding movement of the wheel when the axis of the grinding wheel intersects the axis of rotation of the work. This insures that the side face of the grinding wheel is tangent to the circle of intersection of the two conical surfaces when the wheel is in its final position. The potential adjustment of the work head and work piece through movement along guideways H in a direction parallel with the plane of the grinding wheel l1 permits an exact size compensation for wear of the grinding wheel since when the axis of rotation of the grinding wheel is aligned in a horizontal plane with the axis of rotation of the work, the active edge of the grinding wheel, as indicated in Figure 3, will be at its extreme forward location and relative feeding eifectable as by screw l3 will insure production of surface 44 in exact desired axial relationship to the preformed surface 4|,

For purposes of adjustment to insure that the circle is the correct diameter, the headstock is mounted for cross adjustment on guideways 15 relative to its sub-support i4. This is effected by a cross screw 16, Figure 2, which is anchored at 11 in the sub-support i4 and engages a threaded bore 18 in the headstockas shown in Figure 1.

' A truing mechanism, indicated generally by the reference numeral 19, has been provided which may be of any conventional type having a diamond holder bar 80 slidably mounted in a cross slide 8| which may be reciprocated to carry the diamond 82 across the face of the grinding wheel 11. The holder bar carries a follower 83 which is yieldably held in engagement with a sine bar 84 which is set to yield the desired angularity of the face of the grinding wheel. Since the truing mechanism, however, does not form part of the present invention,'further description thereof is not believed to be necessary.

There has thus been provided an improved grinding machine having new and improved means for supporting and rotating a work piece whereby a preformed surface thereon may be utilized to determine the axis of rotation of the on in concentric relation to the preformed surmeans for holding the work against axial movement whereby the plane of the circle is fixed in space, a. grinding wheel supported for rotation about an axis intersecting the work and having a grinding face which extends parallel to the surface to be produced, said grinding'wheel being positioned longitudinally of its axis in such position that one edge of the wheel lies in a plane thatis tangent to said circle of intersection, means to feed the grinding wheel laterally of its axis into engagement with thework, and means to limit the feeding of the wheel when one peripheral edge of the wheel reaches the circle of intersection.

2. In a grinding machine for grinding an internal conical surface on a work piece with its axis coincident with the axis of a preformed conical surface thereon, the combination of means for supporting the work piece for rotation on its preformed conical surface whereby the axis of rotation of the work will be coincident with the axis of the preformed conical surface, means for holding the work against axial movement during rotation, power operable means for rotating the work, a grinding wheel supported for rotation about an axis that potentially intersects the axis of the preformed conical surface, said grinding wheel having faces which intersect in an acute angle of lesser magnitude than the angle of intersection of the conical surfaces, the plane of intersection of the faces on the grinding wheel being tangent to the circle of intersection of the conical surfaces on the work, and means to feed the grinding wheel parallel to said plane to effect grinding of the conical surface.

3. In a grinding machine, the combination of a face plate, a pressure head for holding a work piece in frictional engagement with said plate, power operable means for rotating the plate and thereby the work, means engageable with the pe. riphery of the work for holding it against lateral movement during rotation with its axis in predetermined position, said plate having its axis of rotation eccentrically disposed as respects the support determined axis of the work, and a grinding wheel movable into engagement with the work for grinding a surface of revolution thereon which is concentric to the axis of rotation.

4. In a grinding machine, the combination of a rotatable face plate, a pressure head supported in opposition to the plate for holding a work piece in frictional engagement therewith, a. work rest having work engaging portions extending longitudinally of the work for determining the axis of rotation thereof, power operable means for rotating the plate means supporting the plate with its axis of rotation in eccentric relation to the work, thereby causing movement of the work by centrifugal force into engagement with the piece so that other surfaces may be ground therework rest, a grinding wheel supported for rotation about an axis intersecting the axis of rotation of the work for grinding a work surface having its axis coincident with the axis of rotation of the work.

5. In a grinding machine having a rotatable face plate, the comibnation' of a work rest mounted adjacent the plate for supporting a work piece with its axis eccentric to the axis of rotation of the plate, a pressure head for engaging and holding the work piece in frictional engagement with the face plate, power operable means for rotating the plate to drive the work by frictional engagement therewith, rotation of the plate producing a centrifugal force which holds the work into engagement with the work rest during rotation thereof whereby the axis of rotation of the work is fixed in space, a grinding wheel supported for rotation about an axis which potentially intersects the axis of rotation of the work, and means to effect lateral movement of the grinding wheel into engagement with the work for producing a surface of revolution thereon concentric with the axis of rotation of the work.

6. In a grinding machine for producing a surface of revolution concentric to the axis of a preformed surface of revolution on the work piece, said work piece having an end face finished in perpendicular relation to the axis of the preformed surface, the combination of a platen, a pressure head for holding a work piece with its end face in frictional engagement with said platen whereby the axis is perpendicular to said platen, means engageable with the pre formed surface on the work for supporting the same eccentric to the axis of the platen, power operable means for rotating said platen whereby the work will be rotated through frictional engagement therewith and will be held by centrifugal force into engagement with said work rest, and a grinding wheel for grinding a surface on the work with its axis coincident with the axis of rotation of the work and thereby with the axis of said preformed surface.

7. In a grinding machine, the combination of a rotatable platen, an axially movable pressure head supported in alignment with the platen whereby a rotatable work piece may be frictionally gripped between them, a work rest blade for engaging the periphery of the work, means to adjust said blade and thereby adjust the axis of the work in a prescribed eccentric relation to the axis of the platen whereby upon rotation of the platen a centrifugal force will be developed which will hold the work piece in engagement with the work rest blade during rotation thereof, and a grinding wheel movalole into engagement with the work for grinding a surface of revolution thereof concentric to its axis of rotation.

8. In a grinding machine, the combination of a work rest blade for supporting a work piece in space, means frictionally engaging the terminals of said work piece, one of said means being a driver, the axis of rotation of which is eccentric to the axis of the work, power means for rotating said driver and work whereby the work will be forcibly held in engagement with said blade by centrifugal force to fix the axis of rotation of the work in space, a grinding wheel supported for rotation about an axis intersecting the axis of rotation of the work, and means to feed the grinding wheel into engagement with the work for producing a surface of revolution thereon concentric to the axis of the work.

9. In a grinding machine having a support, a grinding wheel and means to mount the grinding wheel on the support for oscillatory movement lateral to its axis, the combination of a work support, means to effect longitudinal adjustment of the work support parallel to the plane of oscillation of the grinding wheel, means mounted on the work support for supporting and rotating a work piece about an axis making an acute angle with the plane of rotation of the grinding wheel, and means to feed the grinding wheel into engagement with the work whereby a surface will be produced onthe work making an acute angle with the axis of rotation thereof.

10. In a grinding machine having a bed and a grinding wheel support pivotally mounted on the bed for oscillatory movement, the combination of a slide guided on said bed, work holding means mounted on the slide for supporting and rotating a work piece about an axis making an acute angle to the plane of rotation of the grinding wheel, means to oscillate the grinding wheel toward and from the work, and means to adjust said work holding means whereby the axis of the grinding wheel will intersect the axis of the work when the grinding wheel completes its grinding action.

11. In a grinding machine having a bed and a grinding wheel support pivotally mounted on the bed for oscillatory movement, the combination of a slide guided on said bed, work holding means mounted on the slide for supporting and rotating a work piece about an axis making an acute angle to the plane of rotation of the grinding wheel, means to oscillate the grinding wheel toward and from the work, means to adjust said work holding means whereby the axis of the grinding wheel will intersect the axis of the work when the grinding wheel completes its grinding action, and cam means for feeding the grinding wheel support relative to the work support.

12, A machine for production of the base rib surface in predetermined relation to a preformed conical surface on a race for roller bearings or thelike including a work rest having angularly related work supporting surfaces for engagement of the preformed periphery of the work piece, an end plate adjacent the work rest for terminal engagement with a work piece, means for determining the relative positioning of said parts and thus the alignment or eccentricity of the work piece axis with respect to that of the end plate, means for clamping a work piece against the end plate, means for rotating the end plate to impart a frictional drive against the work piece in a direction to hold it into the V of the work support, a grinding wheel adjustably supported adjacent the work rest and projectable to engage its periphery with the rib on the work piece and with its axis substantially aligned with the axis of the work piece, and means for effecting relative feeding movements of the grinding wheel and work piece whereby the grinding wheel will generate a prescribed surface on the rib concentrio with the preformed surface of the work piece.

13. A machine for production of the base rib surface in predetermined relation to a preformed conical surface on a' race for roller hearings or the like including a work rest having angularly related work supporting surfaces for engagement of the preformed periphery of the work piece, an end plate adjacent the work rest for terminal engagement with a work piece, means for determining the relative positioning of said parts and thus the alignment or eccentricity of the work piece axis with respect to that of -the end plate, means for clamping a work piece 7 to engage its periphery with the rib on the work piece and with its axis substantially aligned with the axis of the work piece, means for efiect- 'ingrelative feeding movements of the grinding wheel and work piece whereby the grinding wheel will generate a prescribed surface on the rib concentric with the preformed suri'ace ot the work piece, and additional means for efiecting a bodily movement of the work piece in the direction 0! the active face of the grinding wheel.

FREDERICK J. THELER. 

